Deuterium-enriched oxybutynin

ABSTRACT

The present application describes deuterium-enriched oxybutynin, pharmaceutically acceptable salt forms thereof, and methods of treating using the same.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority benefit as a Continuation of U.S. patent application Ser. No. 11/757,333, filed 1 Jun. 2007, now allowed. The disclosure of this application is incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates generally to deuterium-enriched oxybutynin, pharmaceutical compositions containing the same, and methods of using the same.

BACKGROUND OF THE INVENTION

Oxybutynin, shown below, is a well known anticholinergic.

Since oxybutynin is a known and useful pharmaceutical, it is desirable to discover novel derivatives thereof. Oxybutynin is described in G.B. Patent No. 940,540; the contents of which are incorporated herein by reference.

SUMMARY OF THE INVENTION

Accordingly, one object of the present invention is to provide deuterium-enriched oxybutynin or a pharmaceutically acceptable salt thereof.

It is another object of the present invention to provide pharmaceutical compositions comprising a pharmaceutically acceptable carrier and a therapeutically effective amount of at least one of the deuterium-enriched compounds of the present invention or a pharmaceutically acceptable salt thereof.

It is another object of the present invention to provide a method for treating overactive bladder, comprising administering to a host in need of such treatment a therapeutically effective amount of at least one of the deuterium-enriched compounds of the present invention or a pharmaceutically acceptable salt thereof.

It is another object of the present invention to provide a novel deuterium-enriched oxybutynin or a pharmaceutically acceptable salt thereof for use in therapy.

It is another object of the present invention to provide the use of a novel deuterium-enriched oxybutynin or a pharmaceutically acceptable salt thereof for the manufacture of a medicament (e.g., for the treatment of overactive bladder).

These and other objects, which will become apparent during the following detailed description, have been achieved by the inventor's discovery of the presently claimed deuterium-enriched oxybutynin.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Deuterium (D or ²H) is a stable, non-radioactive isotope of hydrogen and has an atomic weight of 2.0144. Hydrogen naturally occurs as a mixture of the isotopes ¹H (hydrogen or protium), D (²H or deuterium), and T (³H or tritium). The natural abundance of deuterium is 0.015%. One of ordinary skill in the art recognizes that in all chemical compounds with a H atom, the H atom actually represents a mixture of H and D, with about 0.015% being D. Thus, compounds with a level of deuterium that has been enriched to be greater than its natural abundance of 0.015%, should be considered unnatural and, as a result, novel over their non-enriched counterparts.

All percentages given for the amount of deuterium present are mole percentages.

It can be quite difficult in the laboratory to achieve 100% deuteration at any one site of a lab scale amount of compound (e.g., milligram or greater). When 100% deuteration is recited or a deuterium atom is specifically shown in a structure, it is assumed that a small percentage of hydrogen may still be present. Deuterium-enriched can be achieved by either exchanging protons with deuterium or by synthesizing the molecule with enriched starting materials.

The present invention provides deuterium-enriched oxybutynin or a pharmaceutically acceptable salt thereof. There are thirty-one hydrogen atoms in the oxybutynin portion of oxybutynin as show by variables R₁-R₃₁ in formula I below.

The hydrogens present on oxybutynin have different capacities for exchange with deuterium. Hydrogen atom R₁ is easily exchangeable under physiological conditions and, if replaced by a deuterium atom, it is expected that it will readily exchange for a proton after administration to a patient. The remaining hydrogen atoms are not easily exchangeable and may be incorporated by the use of deuterated starting materials or intermediates during the construction of oxybutynin. Oxybutynin with R₂₂-R₃₁=D is known (Patrick, K. S., et al., “Gas chromatographic-mass spectrometric analysis of plasma oxybutynin using a deuterated internal standard,” J. Chromatog. 1989, 487, 90-98). Oxybutynin with R₂₀-R₂₁=D is known (Lindeke, B., et al., “Metabolism of oxybutynin: Establishment of desethyloxybutynin and oxybutynine N-oxide formation in rat liver preparations using deuterium substitution and gas chromatographic mass spectrometric analysis,” Biomed. Mass Spect. 1981, 8, 506-513).

The present invention is based on increasing the amount of deuterium present in oxybutynin above its natural abundance. This increasing is called enrichment or deuterium-enrichment. If not specifically noted, the percentage of enrichment refers to the percentage of deuterium present in the compound, mixture of compounds, or composition. Examples of the amount of enrichment include from about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 16, 21, 25, 29, 33, 37, 42, 46, 50, 54, 58, 63, 67, 71, 75, 79, 84, 88, 92, 96, to about 100 mol %. Since there are 31 hydrogens in oxybutynin, replacement of a single hydrogen atom with deuterium would result in a molecule with about 3% deuterium enrichment. In order to achieve enrichment less than about 3%, but above the natural abundance, only partial deuteration of one site is required. Thus, less than about 3% enrichment would still refer to deuterium-enriched oxybutynin.

With the natural abundance of deuterium being 0.015%, one would expect that for approximately every 6,667 molecules of oxybutynin (1/0.00015=6,667), there is one naturally occurring molecule with one deuterium present. Since oxybutynin has 31 positions, one would roughly expect that for approximately every 206,677 molecules of oxybutynin (31×6,667), all 31 different, naturally occurring, mono-deuterated oxybutynins would be present. This approximation is a rough estimate as it doesn't take into account the different exchange rates of the hydrogen atoms on oxybutynin. For naturally occurring molecules with more than one deuterium, the numbers become vastly larger. In view of this natural abundance, the present invention, in an embodiment, relates to an amount of an deuterium enriched compound, whereby the enrichment recited will be more than naturally occurring deuterated molecules.

In view of the natural abundance of deuterium-enriched oxybutynin, the present invention also relates to isolated or purified deuterium-enriched oxybutynin. The isolated or purified deuterium-enriched oxybutynin is a group of molecules whose deuterium levels are above the naturally occurring levels (e.g., 3%). The isolated or purified deuterium-enriched oxybutynin can be obtained by techniques known to those of skill in the art (e.g., see the syntheses described below).

The present invention also relates to compositions comprising deuterium-enriched oxybutynin. The compositions require the presence of deuterium-enriched oxybutynin which is greater than its natural abundance. For example, the compositions of the present invention can comprise (a) a μg of a deuterium-enriched oxybutynin; (b) a mg of a deuterium-enriched oxybutynin; and, (c) a gram of a deuterium-enriched oxybutynin.

In an embodiment, the present invention provides an amount of a novel deuterium-enriched oxybutynin.

Examples of amounts include, but are not limited to (a) at least 0.01, 0.02, 0.03, 0.04, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, to 1 mole, (b) at least 0.1 moles, and (c) at least 1 mole of the compound. The present amounts also cover lab-scale (e.g., gram scale), kilo-lab scale (e.g., kilogram scale), and industrial or commercial scale (e.g., multi-kilogram or above scale) quantities as these will be more useful in the actual manufacture of a pharmaceutical. Industrial/commercial scale refers to the amount of product that would be produced in a batch that was designed for clinical testing, formulation, sale/distribution to the public, etc.

In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof.

wherein R₁-R₃₁ are independently selected from H and D; and the abundance of deuterium in R₁-R₃₁ is at least 3%, provided that the compound is other than one where only R₂₂-R₃₁ or R₂₀-R₂₁ are D. The abundance can also be (a) at least 6%, (b) at least 13%, (c) at least 19%, (d) at least 26%, (e) at least 32%, (f) at least 39%, (g) at least 45%, (h) at least 52%, (i) at least 58%, (j) at least 65%, (k) at least 71%, (l) at least 77%, (m) at least 84%, (n) at least 90%, (o) at least 97%, and (p) 100%.

In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₁ is at least 100%.

In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₁, R₂₀-R₂₁, and R₂₂-R₃₁ is at least 8%, provided that the compound is other than one where only R₂₂-R₃₁ or R₂₀-R₂₁ are D. The abundance can also be (a) at least 15%, (b) at least 23%, (c) at least 31%, (d) at least 38%, (e) at least 46%, (f) at least 54%, (g) at least 62%, (h) at least 69%, (i) at least 77%, (j) at least 85%, (k) at least 92%, and (l) 100%.

In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₂₀-R₂₁ and R₂₂-R₃₁ is at least 8%, provided that the compound is other than one where only R₂₂-R₃₁ or R₂₀-R₂₁ are D. The abundance can also be (a) at least 17%, (b) at least 25%, (c) at least 33%, (d) at least 42%, (e) at least 50%, (f) at least 58%, (g) at least 67%, (h) at least 75%, (i) at least 83%, (j) at least 92%, and (k) 100%.

In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₂-R₆ is at least 20%. The abundance can also be (a) at least 40%, (b) at least 60%, (c) at least 80%, and (d) 100%.

In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₇-R₁₇ is at least 9%. The abundance can also be (a) at least 18%, (b) at least 27%, (c) at least 36%, (d) at least 45%, (e) at least 56%, (f) at least 64%, (g) at least 73%, (h) at least 82%, (i) at least 91%, and (j) 100%.

In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof.

wherein R₁-R₃₁ are independently selected from H and D; and the abundance of deuterium in R₁-R₃₁ is at least 3%, provided that the compound is other than one where only R₂₂-R₃₁ or R₂₀-R₂₁ are D. The abundance can also be (a) at least 6%, (b) at least 13%, (c) at least 19%, (d) at least 26%, (e) at least 32%, (f) at least 39%, (g) at least 45%, (h) at least 52%, (i) at least 58%, (j) at least 65%, (k) at least 71%, (l) at least 77%, (m) at least 84%, (n) at least 90%, (o) at least 97%, and (p) 100%.

In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₁ is at least 100%.

In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₁, R₂₀-R₂₁, and R₂₂-R₃₁ is at least 8%, provided that the compound is other than one where only R₂₂-R₃₁ or R₂₀-R₂₁ are D. The abundance can also be (a) at least 15%, (b) at least 23%, (c) at least 31%, (d) at least 38%, (e) at least 46%, (f) at least 54%, (g) at least 62%, (h) at least 69%, (i) at least 77%, (j) at least 85%, (k) at least 92%, and (l) 100%.

In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₂₀-R₂₁ and R₂₂-R₃₁ is at least 8%, provided that the compound is other than one where only R₂₂-R₃₁ or R₂₀-R₂₁ are D. The abundance can also be (a) at least 17%, (b) at least 25%, (c) at least 33%, (d) at least 42%, (e) at least 50%, (f) at least 58%, (g) at least 67%, (h) at least 75%, (i) at least 83%, (j) at least 92%, and (k) 100%.

In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₂-R₆ is at least 20%. The abundance can also be (a) at least 40%, (b) at least 60%, (c) at least 80%, and (d) 100%.

In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₇-R₁₇ is at least 9%. The abundance can also be (a) at least 18%, (b) at least 27%, (c) at least 36%, (d) at least 45%, (e) at least 56%, (f) at least 64%, (g) at least 73%, (h) at least 82%, (i) at least 91%, and (j) 100%.

In another embodiment, the present invention provides novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof.

wherein R₁-R₃₁ are independently selected from H and D; and the abundance of deuterium in R₁-R₃₁ is at least 3%, provided that the compound is other than one where only R₂₂-R₃₁ or R₂₀-R₂₁ are D. The abundance can also be (a) at least 6%, (b) at least 13%, (c) at least 19%, (d) at least 26%, (e) at least 32%, (f) at least 39%, (g) at least 45%, (h) at least 52%, (i) at least 58%, (j) at least 65%, (k) at least 71%, (l) at least 77%, (m) at least 84%, (n) at least 90%, (o) at least 97%, and (p) 100%.

In another embodiment, the present invention provides a novel mixture of, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₁ is at least 100%.

In another embodiment, the present invention provides a novel mixture of, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₁, R₂₀-R₂₁, and R₂₂-R₃₁ is at least 8%, provided that the compound is other than one where only R₂₂-R₃₁ or R₂₀-R₂₁ are D. The abundance can also be (a) at least 15%, (b) at least 23%, (c) at least 31%, (d) at least 38%, (e) at least 46%, (f) at least 54%, (g) at least 62%, (h) at least 69%, (i) at least 77%, (j) at least 85%, (k) at least 92%, and (l) 100%.

In another embodiment, the present invention provides a novel mixture of, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₂₀-R₂₁ and R₂₂-R₃₁ is at least 8%, provided that the compound is other than one where only R₂₂-R₃₁ or R₂₀-R₂₁ are D. The abundance can also be (a) at least 17%, (b) at least 25%, (c) at least 33%, (d) at least 42%, (e) at least 50%, (f) at least 58%, (g) at least 67%, (h) at least 75%, (i) at least 83%, (j) at least 92%, and (k) 100%.

In another embodiment, the present invention provides a novel mixture of, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₂-R₆ is at least 20%. The abundance can also be (a) at least 40%, (b) at least 60%, (c) at least 80%, and (d) 100%.

In another embodiment, the present invention provides a novel mixture of, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R₇-R₁₇ is at least 9%. The abundance can also be (a) at least 18%, (b) at least 27%, (c) at least 36%, (d) at least 45%, (e) at least 56%, (f) at least 64%, (g) at least 73%, (h) at least 82%, (i) at least 91%, and (j) 100%.

In another embodiment, the present invention provides novel pharmaceutical compositions, comprising: a pharmaceutically acceptable carrier and a therapeutically effective amount of a deuterium-enriched compound of the present invention.

In another embodiment, the present invention provides a novel method for treating overactive bladder comprising: administering to a patient in need thereof a therapeutically effective amount of a deuterium-enriched compound of the present invention.

In another embodiment, the present invention provides an amount of a deuterium-enriched compound of the present invention as described above for use in therapy.

In another embodiment, the present invention provides the use of an amount of a deuterium-enriched compound of the present invention for the manufacture of a medicament (e.g., for the treatment of overactive bladder).

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. This invention encompasses all combinations of preferred aspects of the invention noted herein. It is understood that any and all embodiments of the present invention may be taken in conjunction with any other embodiment or embodiments to describe additional more preferred embodiments. It is also to be understood that each individual element of the preferred embodiments is intended to be taken individually as its own independent preferred embodiment. Furthermore, any element of an embodiment is meant to be combined with any and all other elements from any embodiment to describe an additional embodiment.

DEFINITIONS

The examples provided in the definitions present in this application are non-inclusive unless otherwise stated. They include but are not limited to the recited examples.

The compounds of the present invention may have asymmetric centers. Compounds of the present invention containing an asymmetrically substituted atom may be isolated in optically active or racemic forms. It is well known in the art how to prepare optically active forms, such as by resolution of racemic forms or by synthesis from optically active starting materials. All processes used to prepare compounds of the present invention and intermediates made therein are considered to be part of the present invention. All tautomers of shown or described compounds are also considered to be part of the present invention.

“Host” preferably refers to a human. It also includes other mammals including the equine, porcine, bovine, feline, and canine families.

“Treating” or “treatment” covers the treatment of a disease-state in a mammal, and includes: (a) preventing the disease-state from occurring in a mammal, in particular, when such mammal is predisposed to the disease-state but has not yet been diagnosed as having it; (b) inhibiting the disease-state, e.g., arresting it development; and/or (c) relieving the disease-state, e.g., causing regression of the disease state until a desired endpoint is reached. Treating also includes the amelioration of a symptom of a disease (e.g., lessen the pain or discomfort), wherein such amelioration may or may not be directly affecting the disease (e.g., cause, transmission, expression, etc.).

“Therapeutically effective amount” includes an amount of a compound of the present invention that is effective when administered alone or in combination to treat the desired condition or disorder. “Therapeutically effective amount” includes an amount of the combination of compounds claimed that is effective to treat the desired condition or disorder. The combination of compounds is preferably a synergistic combination. Synergy, as described, for example, by Chou and Talalay, Adv. Enzyme Regul. 1984, 22:27-55, occurs when the effect of the compounds when administered in combination is greater than the additive effect of the compounds when administered alone as a single agent. In general, a synergistic effect is most clearly demonstrated at sub-optimal concentrations of the compounds. Synergy can be in terms of lower cytotoxicity, increased antiviral effect, or some other beneficial effect of the combination compared with the individual components.

“Pharmaceutically acceptable salts” refer to derivatives of the disclosed compounds wherein the parent compound is modified by making acid or base salts thereof. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of the basic residues. The pharmaceutically acceptable salts include the conventional quaternary ammonium salts of the parent compound formed, for example, from non-toxic inorganic or organic acids. For example, such conventional non-toxic salts include, but are not limited to, those derived from inorganic and organic acids selected from 1,2-ethanedisulfonic, 2-acetoxybenzoic, 2-hydroxyethanesulfonic, acetic, ascorbic, benzenesulfonic, benzoic, bicarbonic, carbonic, citric, edetic, ethane disulfonic, ethane sulfonic, fumaric, glucoheptonic, gluconic, glutamic, glycolic, glycollyarsanilic, hexylresorcinic, hydrabamic, hydrobromic, hydrochloric, hydroiodide, hydroxymaleic, hydroxynaphthoic, isethionic, lactic, lactobionic, lauryl sulfonic, maleic, malic, mandelic, methanesulfonic, napsylic, nitric, oxalic, pamoic, pantothenic, phenylacetic, phosphoric, polygalacturonic, propionic, salicyclic, stearic, subacetic, succinic, sulfamic, sulfanilic, sulfuric, tannic, tartaric, and toluenesulfonic.

Synthesis

Scheme 1 shows two routes to oxybutynin (Majewski and Campbell, U.S. Pat. No. 3,176,019).

Scheme 2 shows how various deuterated starting materials and intermediates that can be used in the chemistry of Scheme 1 to make deuterated oxybutynin analogs. A person skilled in the art of organic synthesis will recognize that these materials may be used in various combinations to access a variety of deuterated oxybutynins. This FIGURE is meant to be illustrative and not comprehensive; it should be recognized that a person skilled in the art of organic synthesis will readily derive other chemical reactions and deuterated materials that may be used to make a wide variety of oxybutynin analogs. The use of the deuterated amine 4 in the synthesis of 2 or in equation (2) in Scheme 1 will produces oxybutynin with R₂₂-R₃₁=D. The use of the deuterated amine 5 in the synthesis of 2 or in equation (2) in Scheme 1 will produces oxybutynin with R₂₂-R₂₅=D. The use of the deuterated amine 6 in the synthesis of 2 or in equation (2) in Scheme 1 will produces oxybutynin with R₂₆-R₃₁=D. The use of the deuterated formaldehyde 7 in the synthesis of 2 or in equation (2) in Scheme 1 will produces oxybutynin with R₂₀-R₂₁=D. The use of 8, a deuterated form of 1, in equation (1) in Scheme 1 will produces oxybutynin with R₂-R₆=D. The use of 9, a deuterated form of 1, in equation (1) in Scheme 1 will produces oxybutynin with R₇-R₁₇=D. The use of 10, a deuterated form of 3, in equation (2) in Scheme 1 will produces oxybutynin with R₂₀-R₂₁=D.

Examples

Table 1 provides compounds that are representative examples of the present invention. When one of R₁-R₃₁ is present, it is selected from H or D.

Table 2 provides compounds that are representative examples of the present invention. Where H is shown, it represents naturally abundant hydrogen.

Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise that as specifically described herein. 

1. A method for treating overactive bladder comprising: administering, to a patient in need thereof, a therapeutically effective amount of a deuterium-enriched compound of formula I or a pharmaceutically acceptable salt thereof:

wherein R₁-R₃₁ are independently selected from H and D; and the abundance of deuterium in R₁-R₃₁ is at least 3% provided that the compound is other than: (a) a compound where each of R₂₂-R₃₁ is D or (b) a compound where each of R₂₀-R₂₁ is D.
 2. The method of claim 1, wherein the abundance of deuterium in R₁-R₃₁ is selected from at least 3%, at least 6%, at least 13%, at least 19%, at least 26%, at least 32%, at least 39%, at least 45%, at least 52%, at least 58%, at least 65%, at least 71%, at least 77%, at least 84%, at least 90%, at least 97%, and 100%.
 3. The method of claim 1, wherein the abundance of deuterium in R₁ is 100%.
 4. The method of claim 1, wherein the abundance of deuterium in R₁, R₂₀-R₂₁, and R₂₂-R₃₁ is selected from at least 8%, at least 15%, at least 23%, at least 31%, at least 38%, at least 46%, at least 54%, at least 62%, at least 69%, at least 77%, at least 85%, at least 92%, and 100%.
 5. The method of claim 1, wherein the abundance of deuterium in R₂₀-R₂₁ and R₂₂-R₃₁ is selected from at least 8%, at least 17%, at least 25%, at least 33%, at least 42%, at least 50%, at least 58%, at least 67%, at least 75%, at least 83%, at least 92%, and 100%.
 6. The method of claim 1, wherein the abundance of deuterium in R₂-R₆ is selected from at least 20%, at least 40%, at least 60%, at least 80%, and 100%.
 7. The method of claim 1, wherein the abundance of deuterium in R₇-R₁₇ is selected from at least 9%, at least 18%, at least 27%, at least 36%, at least 45%, at least 56%, at least 64%, at least 73%, at least 82%, at least 91%, and 100%.
 8. The method of claim 1, wherein the compound is selected from compounds 1-8 of Table 1:


9. The method of claim 1, wherein the compound is selected from compounds 9-16 of Table 2:


10. A method for treating overactive bladder comprising: administering, to a patient in need thereof, a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt thereof:

wherein R₁-R₃₁ are independently selected from H and D; and the abundance of deuterium in R₁-R₃₁ is at least 3% provided that the compound is other than: (a) a compound where each of R₂₂-R₃₁ is D or (b) a compound where each of R₂₀-R₂₁ is D.
 11. The method of claim 10, wherein the abundance of deuterium in R₁-R₃₁ is selected from at least 3%, at least 6%, at least 13%, at least 19%, at least 26%, at least 32%, at least 39%, at least 45%, at least 52%, at least 58%, at least 65%, at least 71%, at least 77%, at least 84%, at least 90%, at least 97%, and 100%.
 12. The method of claim 10, wherein the abundance of deuterium in R₁ is 100%.
 13. The method claim 10, wherein the abundance of deuterium in R₁, R₂₀-R₂₁, and R₂₂-R₃₁ is selected from at least 8%, at least 15%, at least 23%, at least 31%, at least 38%, at least 46%, at least 54%, at least 62%, at least 69%, at least 77%, at least 85%, at least 92%, and 100%.
 14. The method of claim 10, wherein the abundance of deuterium in R₂₀-R₂₁ and R₂₂-R₃₁ is selected from at least 8%, at least 17%, at least 25%, at least 33%, at least 42%, at least 50%, at least 58%, at least 67%, at least 75%, at least 83%, at least 92%, and 100%.
 15. The method of claim 10, wherein the abundance of deuterium in R₂-R₆ is selected from at least 20%, at least 40%, at least 60%, at least 80%, and 100%.
 16. The method of claim 10, wherein the abundance of deuterium in R₇-R₁₇ is selected from at least 9%, at least 18%, at least 27%, at least 36%, at least 45%, at least 56%, at least 64%, at least 73%, at least 82%, at least 91%, and 100%.
 17. The method of claim 10, wherein the compound is selected from compounds 1-8 of Table 1:


18. The method of claim 10, wherein the compound is selected from compounds 9-16 of Table 2:


19. A method for treating overactive bladder comprising: administering, to a patient in need thereof, a therapeutically effective amount of a mixture of deuterium-enriched compounds of formula I or a pharmaceutically acceptable salt thereof:

wherein R₁-R₃₁ are independently selected from H and D; and the abundance of deuterium in R₁-R₃₁ is at least 3% provided that the compound is other than: (a) a compound where each of R₂₂-R₃₁ is D or (b) a compound where each of R₂₀-R₂₁ is D.
 20. The method of claim 19, wherein the abundance of deuterium in R₁-R₃₁ is selected from at least 3%, at least 6%, at least 13%, at least 19%, at least 26%, at least 32%, at least 39%, at least 45%, at least 52%, at least 58%, at least 65%, at least 71%, at least 77%, at least 84%, at least 90%, at least 97%, and 100%.
 21. The method of claim 19, wherein the abundance of deuterium in R₁ is 100%.
 22. The method of claim 19, wherein the abundance of deuterium in R₁, R₂₀-R₂₁, and R₂₂-R₃₁ is selected from at least 8%, at least 15%, at least 23%, at least 31%, at least 38%, at least 46%, at least 54%, at least 62%, at least 69%, at least 77%, at least 85%, at least 92%, and 100%.
 23. The method of claim 19, wherein the abundance of deuterium in R₂₀-R₂₁ and R₂₂-R₃₁ is selected from at least 8%, at least 17%, at least 25%, at least 33%, at least 42%, at least 50%, at least 58%, at least 67%, at least 75%, at least 83%, at least 92%, and 100%.
 24. The method of claim 19, wherein the abundance of deuterium in R₂-R₆ is selected from at least 20%, at least 40%, at least 60%, at least 80%, and 100%.
 25. The method of claim 19, wherein the abundance of deuterium in R₇-R₁₇ is selected from at least 9%, at least 18%, at least 27%, at least 36%, at least 45%, at least 56%, at least 64%, at least 73%, at least 82%, at least 91%, and 100%.
 26. The method of claim 19, wherein the compounds are selected from compounds I-8 of Table 1:


27. The method of claim 19, wherein the compounds are selected from compounds 9-16 of Table 2: 